1. Field of the Invention
The present invention relates generally to a system with cordless pressure-sensitivity and electromagnetic-induction, and more particularly to a system with cordless pressure-sensitivity and electromagnetic-induction, wherein the system can emit and receive the specific frequency.
2. Description of the Prior Art
Because a handwriting recognition system could replace the mouse, and is more suitable than the mouse to let the user input words and patterns by user's hands, improvement of the handwriting recognition system is a hot and important field of current computer technology. The original intention of the handwriting recognition system is to replace the mouse. As usual, to enhance the user's convenience, a handwriting recognition system would usually replace the mouse by both wireless pen and tablet. Herein, the pen nib of the wireless pen usually corresponds to the left button of the mouse. Conventional handwriting recognition systems have been developed for many years, but these products are applied to perform only one function, such as drawing or inputting a word.
Usually, a handwriting recognition system is a device with cordless pressure-sensitivity and electromagnetic-induction. FIG. 1 shows a circuit block diagram of a conventional cordless pressure-sensitive and electromagnetic-induction device. Conventional cordless pressure-sensitivity and electromagnetic-induction device comprises: a cordless pen and a tablet. There is an oscillating circuit that consists of LC in the cordless pen. If the pen point is touched, the amount of inductance will be changed that results in the variation of oscillating frequency. The amount of inductance is increased when touching the pen point and increasing pressure so the variation of oscillating frequency is also increased. Therefore, the variation of the pressure on the pen point can be detected by way of the variation of oscillating frequency. There are two switches on the sidewall of the cordless pen, the emitted frequency of the cordless pen can be changed with the capacitance variation of the LC device that is produced by pushing down or setting free the switches. Furthermore, the tablet comprises a detector, a amplifier and an analog-digital converter. In the conventional tablet, there is a detected loop in the center region of the tablet, with one-way antennas located on the double faces of the detected loop, wherein the one-way antennas are equidistantly arranged in order by way of using array. The main purpose of the one-way detected loop is only applied to receive the electromagnetic wave that is emitted by the cordless pen. When the cordless pen emits the electromagnetic wave, the one-way antennas receive the electromagnetic wave, and then the tablet can obtain correlative information by the electromagnetic induction. However, a conventional system with cordless pressure-sensitivity and electromagnetic-induction can only receive the electromagnetic wave from the peripheral apparatus thereof and detect the position of the peripheral apparatus. In accordance with the above description, a new system with cordless pressure-sensitivity and electromagnetic-induction is therefore necessary, so as to strengthen and increase the functions of the apparatus with cordless pressure-sensitivity and electromagnetic-induction.